How do I create only one of multiple new face outcomes?
It seems that there is no easy way to do this automatically in your case.
You can create faces between edges manually by selecting the edges where you want the face to be, and pressing F.

Create the inner faces: Select neighboring edges, and press F



Repeat this for other faces to make the inner cross:



To avoid creating non-quad geometry, we need to subdivide the outer ring to match the edge count of the inner ring. Select the outer edges (you can loop-select by using Alt+ Click), And subdivide them with 2 cuts:


Now we have the same number of edges inside as outside (3 for each side). You can continue this process, making faces where needed, to fill the remaining geometry.
You can also use the Bridge Edge Loops command to fill multiple faces at once.
Alternative Method
There is a much simpler way to create the window-like geometry you want:

Create plane
Subdivide for 2x2 grid
Set the Transform Pivot Point to &quot;Individual origins&quot;



Select all faces; Extrude Individual Faces; Esc to avoid offsetting

Scale (S) the 4 faces to make them smaller:



(This will scale them individually because of step 3)

Delete the unnecessary faces!